Intercellular communication mediated by the extracellular calcium-sensing receptor.

Area of Science:

• Cell Biology
• Physiology
• Biochemistry

Background:

• Intracellular calcium (Ca2+) signaling is crucial for numerous cellular functions.
• Agonist stimulation leads to Ca2+ extrusion, suggesting external Ca2+ concentration ([Ca2+]) changes.
• The physiological role of extracellular [Ca2+] fluctuations has been largely unexplored.

Purpose of the Study:

• To investigate the physiological relevance of extracellular Ca2+ changes during cellular signaling.
• To determine if extracellular Ca2+ signals can be transmitted between cells.
• To explore the role of the calcium-sensing receptor (CaR) in this process.

Main Methods:

• Measurements of extracellular Ca2+ concentration ([Ca2+]) in response to agonist stimulation.
• Co-culture experiments with cells expressing the Ca2+-sensing receptor (CaR).
• Analysis of CaR activation by extracellular Ca2+ signals.

Main Results:

• Agonist-evoked Ca2+ mobilization in one cell generates a detectable extracellular Ca2+ signal.
• This extracellular signal is sensed by neighboring cells expressing the Ca2+-sensing receptor (CaR).
• The CaR mediates the detection of these extracellular Ca2+ signals, indicating intercellular communication.

Conclusions:

• Extracellular Ca2+ concentration ([Ca2+]) changes serve as a form of intercellular communication.
• The calcium-sensing receptor (CaR) plays a key role in detecting these extracellular signals.
• Cells can communicate their Ca2+-signaling status to neighbors via CaR-mediated pathways.